Orthobullets

Question 1

Most common malignant bone tumors ?

Answer 1

MMLPP

Mets
Myeloma
Lymphoma
Pagets sarcoma
Post-rad sarcoma

patients ages 40-80

Question 2

Most common visceral carinomas that spread to bone ?

Answer 2

BLT PK

Breast
Lung
Thyroid
Prostate Kidney

Question 3

Most common sites of metastasis ?

Answer 3

LLB

Lung
Liver
Bone – 3rd !

Spine most common bone site
Thoracic spine most common within the spine

Femur second mc site
neck 50%
subtroch 30%
peritroch 20%

Question 4

Most common bone mets sites ?

Answer 4

Spine mc bone site
thoracic spine

Femur second mc site
neck 50% – mc site for patho fracture
subtroch 30%
peritroch 20%

Humerus third mc site

Question 5

How does tumor cause lytic lesions ?

Answer 5

OC activation
through RANK, RANKL, OPG pathway

Indirectly stimulated through
OB, stromal cell production of cytokines like RANKL

Question 6

How does tumor cause blastic lesions ?

Answer 6

Prostate CA
PTHrp positive breast CA

through RANKL production
ET-1 (endothelin-1) is crucial

Question 7

What is metastatic hypercalcemia ?

What are the symptoms (classfn) ?

What is the management ?

Answer 7

MEDICAL EMERGENCY
Increase total serum Ca level (n= 9-10)

Symptoms
Confusion/muscle weakness
Dehydration/renal insufficiency : polyuria and dypsia
Coma

Management
1- volume depletion = aggressive hydration
2- renal insufficiency = loop diuretics
3- correct electrolyte imbalance = bisphosphonates, calcitonin, denusomab

Question 8

What is life expectancy of common metastatic carcinomas ?

Answer 8

Lung shortest, Thyroid longest

Lung 6 mo
Renal 6 mo - 4/5 yrs; dpt on med PMH at time of dx
Breast 2 yrs
Prostate 3.5 yrs
Thyroid 4 yrs

Question 9

How does metastasis occur (steps) ?

Answer 9

1- intravasation (e-cadherin)
2- avoidance of immune surveillance (pdgf-1)
3- target tissue localization (cxcl-12, I-CAMs)
4- extravasation (MMPs)
5- induction of angiogenesis (vegf)
6- genomic instability
7- decrease apoptosis

Question 10

What are the Work Up Principles of a metastatic lesion ?

What are the associated specifics ?

Answer 10

LABS, IMAGING, and BIOPSY

Labs : CBC with differential, ESR, BMP, LFTs, Ca/Po4 series, ALP, S-PEP and U-PEP

Imaging :
Plain XRs in 2 planes of affected limb and chest
Whole body Tc-99 (according to rugraph et al)
Skeletal survey indicated in myeloma and thryoid CA (bc are often cold on bone scan)
CT chest/abdo/pelvis for mets including to spine
MRI if spinal lesion to detail mass effect

• • 85% of the time diagnosis (rugraph)
• – biopsy only 35% of the time
• —> if cant find primary then BIOPSY must be performed to r/o primary bone tumor

Question 11

Features of common carcinomas on XR ?

Answer 11

(lytic- lung, thyroid, renal)
(blastic- 60% of breast, 90% prostate)
(cortical mets- lung)
(lesions distal to elbow and knee- lung, renal)

Question 12

CASE
60F with 100 pack year history; known Lung CA
No previous diagnosis of metastatic disease
Presents with new lytic lesion in femoral shaft that is high risk for pathologic fracture?

Does she need a biopsy prior to prophylactic IMN ?

Answer 12

YES !!

Note sending reamings in NOT an appropriate biopsy
Ex. if chondrosarc then will require an amputation

But can do open biopsy and prophylactic nailing in same procedure (same GA) if surgical pathologist can confirm carcinoma

Question 13

Name medical management strategies in patients with metastatic bone disease?

Indications for chemo and/or rads and/or hormone therapy?

Answer 13

Prevention of fracture and bone related pain can significantly improve morbidity

Bisphosphonates
IV palmindronate

Breast lung thyroid kidney prostate – all chemo sensitive

All rad sensitive but higher doses for RCC and radio-iodine must be used for thyroid

Regarding hormone therapy - breast can be and androgen deprivation for prostate

Question 14

Indications for prophylactic surgery (by rugraph) for metastatic carcinoma?

Answer 14

1- biological activity of bone lesion
2- responsiveness to medical and radiation therapy
3- anatomic location
4- patient factors- health status, length of survival, compliance, patient expectations/needs

Question 15

Determining operative therapies prior for meastatic carcinoma lesions (by rugraph)?

Answer 15

1- pre-op embolization
IND RCC or Thyroid

2- stabilization of complete fracture, post op rads
Goals - patient survives, immediate full WB, implant survival > patient

3- prophylactic stabilization, post op rads
IND Mirrell’s , Harringtons

Question 16

Do all patients with stabilization (fracture of prophylactic) with metastatic carcinoma get post op rads?

What is the protocol?

Answer 16

All get post op rads unless imminent death or previous rads to the site

Begins shortly after surgery, to improve
Pain, slow progression, treat residual disease

Rads area needs to include length of fixation !!

Question 17

Describe Mirell’s score

Answer 17

Site : UE, LE, peritroch femur
Lesion type : blastic, mixed, lytic
Size : <1/3, 1/3 to 2/3, >2/33 of cortical diameter
Pain : mild, moderate, functional pain

score>7 prophylactic fixation is recommended

Question 18

Prophylactic fixation principles

Answer 18

stable implant protects total bone
full WB

Preferred bc
shorter operative time
decr morbidity
quicker recovery

Question 19

Implant choice for stabilization of metastatic carcinomas based on anatomic locations of humerus and femur ?

Answer 19

Proximal humerus - endoprosthesis
Midshaft humerus - nail, resection and intercalarly spacer, plate and screws (less preferred)
Distal humerus- flexible nails, endoprosthesis

Peritroch and subtroch of femur - statically locked IM or CM nail with currettage and cementing
Neck and head of femur (intra-capsular) - hemiarthroplasty plus minus long stem
If involves acetabulum - THA